Bosch 0445115069 Diesel Injector

OM646 injectors fail in four field-recognisable patterns. The first is a no-start or extended-crank condition on a fully-warm engine — almost always a worn pintle or seized armature on a single cylinder. The second is heavy black smoke under acceleration combined with a measurable loss of pull above 2,500 rpm — symptomatic of over-fuelling on one or more cylinders. The third is rough idle with a perceptible knock that smooths out above 1,500 rpm, often misdiagnosed as turbo or top-end mechanical play. The fourth is excessive leak-back into the rail return system, surfacing as repeat hard-starts on a cold morning after the rail has bled down overnight.

Live-data diagnosis on Mercedes-spec scan tools (Star Diagnosis / XENTRY) is the fastest route to the failed unit. Read individual cylinder fuel-trim corrections, rail-pressure deviation at idle and during cranking, and run a cylinder-by-cylinder leak-off test before tear-down. A single injector returning more than the workshop manual permits at the rail-return port is the unit to replace.

The 0445115069 / 0445115068 family is fitted across the W639 Sprinter (NCV3) 2.2 CDI 209/211/213/215/216/218 (OM646.984/985/986/990, 2006-2009), W639 Vito and Viano 2.2 CDI 109/111/115 (OM646.980/982, 2003-2010), W211 E-Class E200 / E220 CDI (OM646.821/961/984, 2002-2009), W203 C-Class C200 / C220 CDI (OM646.962/963, 2003-2008) and C209 CLK220 CDI (OM646.963, 2005-2009). The OM646.701 industrial sub-code is also covered by this Bosch CRIN family.

All variants share the same Bosch CRIN body, calibration class and copper sealing washer specification — meaning a 0445115069 unit will physically fit any of the above OM646 applications. What changes between vehicles is the ECU calibration map and the cylinder-position correction values, both of which live in the engine ECU rather than the injector itself.

The single most accurate diagnostic for a failing OM646 injector is the leak-off (return-line) test. Disconnect the four return spigots, fit calibrated test bottles to each, crank the engine for 30-60 seconds and measure the volume returned per cylinder. Any injector returning materially more than its three siblings is the failed unit — even if the engine appears to be running smoothly under load.

Hard-start episodes that resolve after several seconds of cranking are almost always traceable to internal leak-back drying out the rail overnight. Rough idle that improves above 1,200 rpm is typically a single-cylinder over-fuelling event caused by a stuck-open injector — readable as a negative fuel-trim correction on that cylinder in live data.

Every Mercedes OM646 injector carries a factory calibration class (typically a single-letter or numeric code laser-marked on the body) which the ECU uses to compensate for unit-to-unit flow tolerance. After fitting a remanufactured 0445115069 / 0445115068 unit, the new calibration value MUST be programmed into the engine ECU against the correct cylinder index. On Sprinter, Vito, Viano, E-Class, C-Class and CLK applications this is done via Mercedes Star Diagnosis / XENTRY or a compatible aftermarket tool that supports CDI3 / CDI4 injector coding.

Skipping the calibration step is the most common cause of a freshly-fitted OM646 injector throwing immediate cylinder-balance, rail-pressure and EGR-flow fault codes. Every unit we ship is delivered with its individual calibration class clearly marked on the packaging and on the injector body itself.

Each OM646 unit is fully stripped, ultrasonically cleaned, fitted with new Bosch genuine internal components (nozzle, pintle, armature, control valve), reassembled to OEM torque spec and bench-tested on Bosch CR918 / EPS 200 calibration equipment across idle, mid-range and full-load delivery profiles. Every unit ships with a printed test certificate showing actual flow values against the OEM tolerance window.

Each remanufactured injector includes the correct copper sealing washer, is supplied with a 12-month warranty, and qualifies for free UK delivery. A £20 refundable core deposit applies — refunded after your old core is received and inspected (return within 30 days of receiving your remanufactured injector).